Artificial wool filament and yarn



Nov. 17, 1942. 2,302,077

HElNZ-HORST E. VON KOHORN zu KORNEGG, NOW BY JUDICIAL CHANGE OF NAMEHENRY VON KOHORN ARTIFICIAL WOOL FILAMENT AND YARN .Original Filed Feb.25, 1939 FL J.

SPINNING BA TH THREAD GU/DE-S INVENTOR. 6 8/71, Van A a/1on7 BY moan. flw ATTORNEYS markings, 200 mm. apart.

Patented Nov. 17, 1942- ARTIFICIAL WOOL FILAMENT AND YARN Heinz-Horst E.Von Kohorn Zu Kornegg, Ne York, N. Y., now by judicial change of nameHenry Von Kohorn, assignor, by mesne assignments, to Fibres Associates,Inc., a corporation of New York Original application February 25, 1939,Serial No. 258,498} Divided and this application June 6, 1940, SerlalNo. 339,117

Claims. (01. 57-140) This invention relates to the manufacture offilaments, threads, yarns, ribbons, staple or'similar fibres and theproducts made therefrom, having the characteristics of natural wool inrespect to appearance, feel, serimetric and physical properties. Iproduce such wool imitation filaments, etc. from cellulose containingvegetable sources according to the viscose method.

It is known that a temporary wool character can be obtained whenproducing filaments from viscose by spinning the viscose at a ripenessgreatly deviating from the customary one. But such wool characteristicsproduced by extraordinary ripeness conditions are not permanent anddisappear during the subsequent treatment of the filaments an d/ ortheir fabrics such as boiling, ironing, etc.

When hereinafter referring to ripeness degree, the so-calledHottenroth-ripeness is meant, which is determined according to thefollowing method: 20 grams of viscose are diluted and mixed with 30 com.of water. Then a ammonium chloride (NH4C1) solution is slowly addeduntil the viscose reaches the coagulation point. The number of cubiccentimeters of NH4CI solution necessary to reach this coagulation pointis the ripeness or ripeness degree of the viscose.

In the drawing:

Fig. 1 is a diagrammatic view of a spinning device upon which theimproved yarn is spun. Fig. 2 is an end view of the finished yarn. Fig.3 is aside view of the same. Fig. 4 is similar to Fig. 2 but showing asmaller air-enclosing canal. The viscosity referred to hereinafter isdetermined according to the b'all-fall method, carried out in thefollowing manner: The viscose under examination is poured into avertical glass tube of 300 mm. length and mm; diameter. The viscoseshould have a temperature of about 18 degrees C. On the glass tube areprovided two A steel ball of 3 mm. diameter and weighing 1.28 grams isdropped into the glass tube, and the time required by the steel ball todrop through the 200 mm. column of viscose between the upper and thelower mark, is measured. The ,numberof seconds required by the steelball to drop said 200mm is the viscosity of the viscose.

*When spinning ordinary viscose rayon or staple fibre, the viscose isspun at a usual ripeness of 7 to 13and a viscosity of 25 to 50.Approximately the same figures are meant when referring hereinafter toordinary or usual ripeness" and ordlnary or usual viscosity.

According to my invention, I obtain filaments, etc., with permanent woolcharacteristics by preparing a viscose of high viscosity and by spinningthis viscose into a bath containing a comparatively large quantity ofcertain salts. Asalt content of 4% zinc sulphate or more, besides thenormal sodium sulphate content, was found very satisfactory for thispurpose. iBut under certain circumstances aluminum sulphate, magnesiumsulphate, ammonium sulphate, nickel sulphate and cobalt sulphate werealso found suitable. It is alsopossible to use a combination of two ormore of the above described salts, always over and above the normalsodium sulphate content. The reason I provide for these salts in myspinning bath is; that these salts not only improve the wool-like feelof the filaments produced according to this process, but I also findthat the presence of these salts at the given high percentagescounteract the drawbacks of spinning a highly? cous viscose. On theother hand, the high viscos of the viscose counteracts the obj'ectionable effe ts\of the high percentage of zinc and other sulphatesmentioned in the spinning bath, which occur, when sing such highpercentages in spinning a viscose of normal viscosity.

When referring in this specification to the high salt content," a saltcontent of 4% zinc sulphate or more, over and above the normal sodiumsulphate content of about 23% ora combination of any two or more of theabove mentioned salts, and having a similar effect as 4% or more zincsulphate, is meant. The above mentioned similar effect" is intended torefer to the wool characteristics of the filaments only.

As mentioned above, various attempts have been made to produce wool-likefilaments by spinning a viscose with abnormal ripeness, both very highand very low. It is, however, known.

to peopleskilled in the art that it is very difiicult to control theripeness of viscose in either a very fresh (unripened) or in a very ripecondition. I have discovered the new and desirable effect of spinning aviscose with a high viscosity but at normal ripeness into a spinningbath containing a high percentage of zinc or similarly acting sulphates,in order to obtain filaments, etc., with a wool characteristic. I havealso discovered that the disadvantage of spinning a viscose with a veryhigh viscosity into a normal spinning bath, and the disadvantages ofspinning a viscose of normal viscosity into a spinning bathcontaining ahigh percentage of zinc sulphate, can be avoided by spinning viscosewith a high viscosity into a spinning bath containing a high percentageof zinc or similarly acting sulphates. In this specification the termspinning viscosity is intended to refer to the viscosity of the viscoseat the time of spinning.

Example 1.Cellulose is treatedin an18% caustic soda solution at 20degrees C. for about one hour and then pressed to retain caustic sodasolution amounting to twice the quantity of cellulose used. Thiscellulose is then shredded into fine crumbs at a temperature of 22-degrees C. The shredded alkali cellulose is then immediately sulphidizedwith 33% carbonbisulphide at a temperature of 22 to 25 degrees C. forabout 90 minutes. The xanthate obtained .is dissolved in a dilute,caustic soda solution, so as to..form a viscose containing 7% alkali and7% alphacellulose, and is stored in tanks. At this point the viscose hasa viscosity of 900 and a ripeness of 13.

The viscose is then filtrated and evacuated immediately, .within about 6hours. During this time the viscosity drops to about-850 andthe ripenessto 12.6. (According to the old method, viscose is stored for about 90hours.)

The viscose is then spun (projected through spinnerets) into a spinningbath containing 11% sulphuric acid,'23% sodium sulphate and 4% zincsulphate at a temperature of 45. degrees C.

The filaments obtained are either collected in one of the known devicesand then washed, bleached, etc., in order to finish them or they can befinished in one continuous operation whilst continuously running.

Example 2.-Viscose prepared according to Example 1 is spun intofilaments on a spinning machine provided with the following devices:

The viscose pump forces the viscose through the spinneret which containsthe number of holes required for the purpose the filaments are providedfor. There is, further a glass wheel provided at a distance from thespinneret. The wheel is driven and runs outside the-spinning bath. Thereis a second glass wheel provided above the first glass wheel.

The viscose projected through the spinneret forms filaments bycoagulation and is withdrawn from the spinneret by the first glass wheelaround which the filaments take up to one complete turn. From here, thethread passes on to and around the second glass wheel which is driven ata peripherical speed greater than that of the first wheel. The number ofturns taken by the filaments around this second wheel depends on theposition of the eventual collecting device. The filaments may be takenup by (a) Bobbins, reels or any other winding-up mechanism,

(17) Pots or buckets,

(c) Rollers or other guiding or feeding devices on which the filaments,whilst continuously running, are subjected to washing and bleaching orthat feed the filaments to be a cutting device.

The immersion length of the filaments in the spinning bath, the positionof the glass wheels and the angles in the direction of the filaments orthreads formed by these wheels must be determined according to thedesired results and will vary with the types of viscose and spinningbath used.

Example 3.Mode of operation as in Example 2 with the difference thatthere may be thread guides provided between the spinneret and the andthe second and between the second glass omitted and that tension isapplied to the fila- 'ments solelyby means of thread guides between the'spinneret and thecollecting device.

In order to obtain a more wool-like feel and appearance of the filaments'produced from viscose pr'epared'according to above mentioned examples,it has been found advisable to coagulate these filaments in loosecondition and to apply the necessary tension after the filaments havebeen formed butwhile they still partly are in a plastic condition.

To this end and as'one embodiment of'my invention, a spinningdeviceas-shown inFigfl and explained in the examples may be used. Afterthe viscose squirted through the spinneret has partly been precipitatedso as to form tubes which still contain fluid viscose'on theinside, theyare given tension only sufficient to withdraw the filaments but-notstretching them immediately after their formation.

After the filaments have thus been given time to take the requiredshape, they are stretched sufficiently by various methods toobtainsufficient strength. This can be done by thread guides, rollers, wheels,'etc., as'described in "the examples.

The composition of the viscose and of the spinning bath cause thefilaments produced to have a rough or cracked surface, similar'to thescales of natural 'wool. Furthermore, the filaments twist insuch-amanner asto have a crosssection similar to a horse shoe, the endsof which touch or overlap, as illustrated in "2 and lined. The distancebetween the spinneret and the (first) drawing-off mechanism is between10 and 30 inches, all of which, or a portion of which may be the actualimmersion length in the spinning bath.

There may be one or two drawing-off mechanisms provided anterior to theeventual collected device. According to the present invention, Iwithdraw the filaments formed from the spinneret under as little tensionas possible so that the initial formation of the filaments whichconsists of the formation of a cellulose tube,\(whi'ch is comparativelyrigid, but which still contains fluid viscose on the inside), takesplace in loose condition. After the filaments have thus been formed,under conditions which allow them to assume the required shape andstructure caused by the effects of the viscose and the spinning bathupon each other, I apply tension or stretch the filaments by increasingthe drawing-offv applied to the filaments while the more plastic orfluid inner part of the filaments will be able to do so, as illustratedin Fig. 3.

I found that it is also possible to apply sufflcient tension to thefilaments to obtain the above described results by conducting filamentsaround thread guides instead of rollers, etc.

The cracked or ruptured surface of the filaments thus formed eventually,improves their wool feel and under proper conditions even resembles thescales of the natural wool fibre. An-

other consequence of this method of spinning is that the filaments takethe shape ofa horseshoe (Fig. 2), the two ends of which almost touch orsometimes overlap, the filaments thus having an air-enclosing space inthecenter which increases the insulation power and thus the warmth ofthe filaments or yarn, fabrics, etc., made from them.

In order to be able to treat the filaments in the above describedmanner, it is important that the coagulation of the viscose and thecomplete regeneration of the cellulose does not take place too quickly.It is known to persons skilled in the I able conditions for eachparticular cellulose used or the type of wool imitation fiber, etc., tobe imitated. Thereare a great many different types of wool ranging fromMerino, which has a very soft feel, to a cross-bred, which is ratherhard to the touch.

When using or referring in this specification to the term filaments,this term is meant to include other viscose products, such as threads,ribbons, fibers and the like.

I am fully aware that neither a high zinc sulphate content in thespinning bath nor an abnormal viscosity of the viscose, nor a stretchingof the filaments after formation are essentially new in themselves, butthis invention con cerns itself with their use and importance in themanufacture of wool imitation filaments, etc., and the new and desirableeffect when used in combination.

Example 6.--Viscose prepared according to Example 1 and spun underconditions and on the devices according to Examples 2 to 4, isprecipitated in a spinning bath having one of the followingcompositions:

Aluminum Sulphuric sulphate acid Sodium sulphate l Magnesium sulphateCobalt i sulphate Ammonium Sulphate Remarks Grams per Grams per literGrams per liter lit Gra ns per er ht Grams per lite Grams per art thatzinc sulphate retards the complete regeneration of' the cellulose byquickly forming a cellulose film or tube on the outside of the tinystream of viscoseprojected through the spinneret. The still fiuidviscose on the inside. of the filament must then be coagulated bymeansof dialysis through this film membrane, thus retarding the completeregeneration of the cellulose.

The filaments obtained according to this method thus have the appearanceand the feel of natural wool, and have at the same time a rough surface,and a hollow, air-enclosing space or canal in the center, as shown inFigs. 2, 3,

and 4.

According to my invention, I apply to the filaments such a tension byconducting them around above mentioned thread guidesor guide rollersplaced at various distances and angles, so as to give the finalfilaments the same elongation as that of the natural wool fibres theyare intended to beblended with, or which theyare to replace.

By regulating the composition of the spinning bath, especially in regardto the quantity of sulphuric acid, I apply the required degree ofhardness or softness to the fibres necessary in order to imitate thenatural wool fibre, especially in regard to their behavior when spuninto yarn. By increasing the quantity of sulphuric acid, it is, forinstance, possible to increase the hardness of the fibres obtained up tothe degree of hardness which certain kinds of wool, as for instancecrossbred, have.

It is impossible to indicate every condition' cellent and of greatuniformity. The reason is that the viscose prepared by my method has avery slow ripening tendency. In distinct contrast to the old method, theviscose prepared by my method changes its ripeness during the course of2 hours, only about 0.1 to 0.15 degree.

It is known that fluctuation in the fineness of viscose are the causefor unev filaments or the fabric even dinary viscose changes i two hourperiod, du wish the contents of one spinning used up (which may form thethre one continuous skein of rayon) by about 0.4, degree. While thisfluctuan olten causes uneven dyeing, the change in oi the viscoseprepared according to my vention of about 0.15 degree is negligible.

When producing filaments, etc., according to above described methods,the filaments have a subdued lustre which may range from a slight to avery distinct dullness. This property is very desirable in view of thefact that natural wool is also dull and that artificial filamentsproduced by this method can be blended with wool or used in the place ofwool without changing the ap pearance of the product at all, comparedwith a woolen product.

This dullness which in contrast to other delustering methods is obtainedwithout the use of chemical additions or mechanical treatments, ispermanent and will not be removed by any subsequent treatment of theproduct.

As it is intended to blend filaments produced according to my methodwith wool or to use them instead of wool, these filaments shouldtherefore resemble natural wool as closely as possible. For thispurpose, the fibers, filaments, etc., produced are intentionally giventhe same physical properties as those of the woolen fibers they are tobe blended with or they are to replace. Such mechanical and physicalproperties. of course, depend on and vary with the different kinds ofnatural wool, and include staple length, cross-section, crimp, surfacecharacter, elasticity, interfibre friction, color, luster, heatconductivity, feel and appearance;

It is obvious that when spinning a yarn'which is to resemble wool, thpercentage of artificial fibres used in this blended yarn cancorrespondingly be increased with an increasing wool-likeness of theartificial fibres. In some cases, even a 100 artificial fibre yarn canbe spun, which has all the mechanical and physical properties of a purewoolen yarn.

After spinning filaments according to one of the above describedmethods, the filaments can either be (in the case of cut staple fibres)(a) Washed, cut and then dried (b) Washed, dried and then cut Cut,washed and dried.

Without limiting myself to the below described method, I prefer tocontinuously wash, cut, and then dry the filaments. A suitable methodand apparatus for carrying out m process are described in United StatesPatent No. 2,134,160. The term washing is meant to includ suchtreatments as de-sulphurizing, bleaching, etc.

In order to give the filaments the same or better crimp than that of thenatural wool fibre, which is very desirable to the spinner when spinningsuch cut filaments into yarn, I dry and treat the filaments as follows:

Prior to drying, I open the cut filaments as Well as possible byfloating them in a large volume of a suitable solution and/ormechanically by passing them through one of the known Wet openers. I dothis because it i known that a larger part of the crimp in artificialfilaments appears during the drying operation and in order for thefilaments to be able to follow this shrinking tendency as much aspossible, it is necessary that the filaments be opened up well and be ina fiufiy condition so as not to prevent them from shrinking,

contracting, twisting and curling by inter-fiber friction.

I have found, however, that on account of the wet condition thefilaments are in when first entering the dryer, it is impossible tocomplete the drying in as loose a condition as seems desirable for thepurpose. dryer as follows:

The dryer is divided into two independent units or sections, each ofwhich can be worked at different speeds, temperatures, humidities, etc.Intermediate these two sections, there is provided a second opener. Thefilaments passing through the first section of the' dryer lose part oftheir moisture content and then pass through this second opener. Thefilaments which ar now only in semi-wet condition are opened much morereadily and are not as clogged together as when opened in wet condition.This second opener can also perform a much more thorough openingoperation because the action on the filaments does not have to be asgentle as when opening completely wet fibers. It is known that viscosefibers are weaker in wet condition than in dry condition and while thefirst opener is to be designed in such a way as to avoid damage bystretching or tearing of the filaments, the second opener may 75 Itherefore have designed my .4

have a much more severe action. The fibres having passed through thesecond opener, enter the second section of the dryer in loose and fiuffycondition and are capable of receivinga curl or crimp in the secondsection of the dryer.

'By this method it is also possible to dry the filaments in the firstsection of the dryer at a much higher temperature because the filamentsstill have a high moisture content. In the second section of the dryerthe temperature is correspondinglylower.

While it has been suggested to comb fibers during the drying operationin order to simplify the carding operation, I believe that I havediscovered the new and desirable effect of an opening operation ofsemi-dry fibers on the crimp of the finished fibers.

The various wool-like properties of the fibres are important both fromthe standpoint of the spinner and the eventual consumer. The followingproperties, for instance, affect the making, i. e., the spinning of theyarn rather than the wearing or use of the fabric: staple length,crosssection, crimp, surface character and inter-fiber friction, all ofwhich have a direct bearing on the spinnability and the cost of the yarnspun. On the other hand, color, lustre, heat conductivity, feel andappearance are properties of importance to the consumer rather than tothe producer. One very important factor, equally important to both, isthe elasticity, as this property affects the spinning as well as thewearing qualities of the fibres to a very large extent.

It is known that the spinning properties of fibres depend, to a largeextent, on the surface structure (smoothness or roughness) of thesefibres. It has always been considered a disadvantage of ordinary cutrayon staples that their surface was too smooth and did not result inthe same goodspinnability as that of cotton or of wool. As describedabove, I therefore, regulate the degree of roughness I apply to thefilaments spun according to my process, by giving them a more or lesscracked and rough surface, comparable to that of wool.

Through my process I am also able to give these artificial woolimitation filaments the same warmth (insulating power) as that of wool.I

accomplish this by giving the filaments the de-' scribed twisted shaperesulting in the air-enclosing canal running in longitudinal directionthrough the whole length of the filaments.

I am able to blend artificial wool imitation filaments producedaccording to my process, amounting to at least 40% with natural wool toform either a composite yarn or a artificial filament yam Such compositeyarns may consist of a wool and cut staple fibre mixture, of a doubledwool yarn and staple fibre yarn or of a doubled woolen yarn andcontinuous filament rayon yarn. In each case the cut fibres, the staplefibre yarn and the continuous filament yarn have been given the abovedescribed wool characteristics.

This is a divisional application of my application Serial No. 258,498,filed February 25, 1939.

I claim:

1. As a new product, a composite yarn consisting of natural wool andartificial wool imitation fibers in which the artificial fibers havebeen made from unadulterated viscose by projecting said viscose througha spinneret into a spinning bath, drawing ofi the filaments under lowtension so as to allow a comparatively rigid cellulose tube containingpartly coagulated visaaoaovv sisting of natural wool and artificial woolimitation fibers in which the artificial fibers have been made fromunadulterated viscose by projecting said viscose through a spinneretinto a spinning bath, containing sulphuric acid, sodium sulphate and atleast 4% zinc sulphate, drawing oil the filaments under low tension soas to allow a comparatively rigid cellulose tube containing partlycoagulated viscose to form on the outside of the filaments, and thenstretching the filaments so as to cause said cellulose tubes to crackand to thus form a rough surface, giving the fibers at least the sameinterfiber friction as that of natural wool and forming a strongercomposite yarn with it.

3. As a new product, a composite yarn consisting of natural wool andartificial wool imitation fibers in which the artificial fibers havebeen made from an unadulterated viscose base and which have been givenduring the manufacture thereof the same properties and characteristicsas natural wool including insulating power and curliness, suchcharacteristics being permanently incorporated in the artificial fibersto withstand all future treatments of the fibers in their normal uses,in order to increase the percentage of artificial fibers in thecomposite yarnto over 40% without materially changing the properties ofthe composite yarn as compared to apure woolen yarn, said artificialfibers having a rough surface formed ,by stretching the fibers duringthe spinning operation to cause a cracking of the outer surface thereof.

' 4. As a new product, a composite yarn consisting of natural wool andartificial wool imitation fibers in which the artificial fibers havebeen made from unadulterated viscose by projecting the viscose through aspinneret into a spinning bath, drawing oil the filaments under lowtension so as to allow a rigid cellulose tube to form on the outside ofthe filaments, stretching the filaments so as to cause said cellulosetubes .to crack and thus form a rough surface, aftertreating thefilaments, cutting the filaments to form staples, subjecting thefilaments to an opening operation, partially drying the filaments,subjecting the partially dried filaments to a second opening operation,and then completing the drying of the filaments to produce a fiberhaving a permanent crimp or curl substantially corresponding, to that ofnatural wool so that the composite yarn will have the characteristics ofnatural yarn.

5. As a new product, a composite yarn consisting of natural wool andartificial wool imitation fibers in which the artificial fibers havebeen made from unadulterated viscose by projecting the viscose through aspinneret into a spinning bath, drawing off the filaments under lowtension so as to allow a rigid cellulose tube to'form on the outside ofthe filaments, stretching the filaments ,so as to cause said cellulosetubes to crack and thus form a rough surface, aftertreating ,thefilaments and drying the filaments to produce fibers having a permanentcrimp or curl substantially corresponding to that of natural wool sothat the composite yarn will have the characteristics of natural yarn.

- H'EINZ-HORST E. VON KOHORN ZU KORNEGG.

